Organic Flashcards
Identify the characteristic of the haloalkane molecule that enables it to undergo a nucleophillic substitution reaction: (Eg in bromo-propane) SPECIFIC
The Polar C-Br bond.
Give a condition needed to favour an elimination reaction in a halogenoalkane rather than a nucleophillic substitution reaction:
-High temperature
Give a use for sulfur dioxide that is formed as a byproduct in a reaction:
To make gypsum / plaster
OR to make H2SO4
Identify one feature of the infrared spectrum which supports the fact that this is an
alcohol. You may find it helpful to refer to Table 1 on the Data Sheet.
Explain how infrared spectroscopy can be used to identify this isomeric alcohol. (3 Marks)
-Peak at 3230-3550
-Run the infrared spectra (of the alcohols)
-Find the one that matches this spectrum
OR
-Peak at 3230-3550
-Use fingerprint region
-And match with spectra in database
Butan-1-ol reacts with acidified potassium dichromate(VI) solution to produce two organic compounds.
Name the two compounds that form.
Butanoic acid CH3CH2CH2COOH
Butanal CH3CH2CH2CHO
Write a equation for the reaction between sodium hydroxide and ethanoic acid.
CH3COOH + NaOH –> CH3COONa + H2O
Reasoning for choosing a rate determining step
-Step which includes the SPECIES in the rate equation
CH3COCH2CH2CH3 CH3CH2COCH2CH3
Two ketone isomers.
Some students were asked to suggest methods to distinguish between isomers Q and R.
One student suggested testing the optical activity of the products formed when Q and
R were reacted separately with HCN.
Explain why this wouldn’t work.
- Product Q is a racemic mixture
- Racemic mixture is optically inactive
- Product from R is inactive as no chiral centre
IUPAC name for glycerol
propane-1,2,3-triol
Give a use for the mixture of sodium salts that form in a reaction with glycerol
Soaps
Give a use for a mixture of methyl esters that form in a reaction with glycerol
biodiesel
Name a suitable reagent for the reduction dinitrobenzene, to a phenyldiamine (benzene with two NH2 groups)
write an equation for this reaction using [H] as the reducing agent
Sn/HCl
C6H4(NO2)2 + 12[H] –> C6H4(NH2)2 +4H20
Repeating unit of kevlar
-(N-H)-benzene-CONH-benzene-(C=O)-
Kevlar used as inner lining of bicycle tires.
Outer tyre made of polymerised alkenes
State the difference in biodegradability of the two.
Use your knowledge of the bonding in these polymer molecules to explain this
difference.
- Kevlar is biodegradable but polyalkenes not
- Kevlar has polar bonds/has peptide link/ is a poly amide
- Can be hydrolysed/attacked by nucleophiles/acids/bases/enzymes
- Polyalkenes not polar/non- polar bonds
Outline a three step synthesis of CH3CH2NH2 starting from methane. Your first step should involve the formation of CH3Cl.
In your answer, identify product of 2nd step and give reagents and conditions for each step
EQUATIONS & MECHANISMS NOT REQUIRED (6 MARKS)
Start with CH3CN
Step 1: React with Cl2 under UV light
Step 2: React with aqueous and alcoholic KCN (Allow UV)
Step 3: React with H2/Ni
Role of hydroxide ion in mechanism:
NOT ‘Nucleophile’
Role is lone pair donor/base
Fermentation reaction with 2 essential conditions:
C6H12O6-----> C2H5OH + 2CO2 Conditions: -No oxygen (anaerobic) -(Enzymes from) yeast -25-42 degrees
Steps for identifying a molecule NMR large 8 mark question;
- State absorbtion peak (eg O-H 3230-3550)
- state peak numbers and infer (4 h1 peaks therefore 4 different hydrogen environments)
- Simplify integration splitting
Give two reasons why Tetramethylsilane is a suitable standard
- Inert
- All protons in same environment
Give an example of a solvent which is suitable for use in recording an nmr spectrum, Give a REASON
- CCl4
- “Proton Free” (means no hydrogen atoms)
What can the reaction of alcohols (eg butan-2-ol) with concentrated sulfuric acid give you?
and name the role of h2so4 in producing byproduct.
Can produce multiple alkenes, and a ketone as a byproduct. (Of the same alkyl eg butan-2-ol would produce multiple different butenes and butanone)
ROLE OF SULFURIC ACID IN KETONE PRODUCTION: OXIDISING AGENT
Role of sulfuric acid when it reacts with solid sodium chloride
Acid
Conditions for catalytic cracking:
- Slight pressure
- High temp
Icicle looking transmittance on nmr spectrum over O-H absorbtion area, is it a peak?
No, noticable peaks are large and wave looking
Is a singlular sharp peak above C=O a peak?
Yes. (If that is the only peak most likely an aldehyde)
Reaction where C3H6 is produced from CH3CH2CH2Br. Identify reagent and conditions:
NaOH and ethanol
Reasons for a molecule not showing stereoisomerism
- Not having a chiral centre
- Symmetrical
State in general terms what determines the distance travelled by a spot in TLC
-Balance between solubility in moving phase and retention by stationary phase
An adverse effect of cisplatin is that it also prevents normal healthy cells from
replicating.
Suggest one way in which cisplatin can be administered so that this side effect is
minimised.
-Use in very small amounts
Primary structure:
The sequence of amino acids along a protein chain
Held together by covalent bonding therefore relatively stable
Can be represented by gly-ala-ala-val-leu
Requires boiling with 6moldm-3 HCl to break amino acids apart
Secondary Structure:
- A protein may form a helix or a folded sheet
- Held in place by hydrogen bonding between C=O groups and N-H groups
Hydrogen bonds are MUCH WEAKER than covalent bonds
Can be easily disrupted by gentle heating or pH change
Tertiary Structure:
Alpha helix or B- pleated sheet can itself be folded into a 3D shape
Held in place by a mixture of hydrogen bonding, ionic interactions and sulfur-sulfur bonds (as well as VDW between all molecules
Finding structure of proteins
Primary:
-First determine the amount of each amino acid present in the protein
So refluxed by 6moldm-3 HCl (hydrolysis, breaks all amide bonds between amino acids and results in a mixture containing all initial amino acids
)
Primary alcohols
Primary alcohols can be oxidised to aldehydes which can
be further oxidised to carboxylic acids.
Secondary Alchohols
Secondary alcohols can be oxidised to ketones
Tertiary alcohol
Tertiary alcohols are not easily oxidised
What are aldehydes readily oxidised to
Aldehydes are readily oxidised to carboxylic acids.
Carboxylic acid reactions
Carboxylic acids and alcohols react, in the presence of an
acid catalyst, to give esters
Explain why the reaction produces a racemic mixture:
- Planar
- Attack from either side
- With equal probability
Benzaldehyde (C6H5CHO) undergoes a dimerisation reaction as shown:
rate = k [C6H5CHO] [CN–]
Suggest the role of the cyanide ion in the reaction.
- Catalyst
- CN– appears in the rate equation but is not in the reaction equation
Zero order
Horizontal line
First order
Straight line going through origin
If you plot a graph against [A]^2 and it ends up with a straight line, what is the order?
Two
Chloroethane reacts with potassium hydroxide in the presence of propan-1-ol
to form ethene.
State the role of potassium hydroxide and the role of propan-1-ol in the reaction.
Potassium hydroxide- Base
Propan-1-ol - Solvent
The structure of polymer A is shown.
Draw the structure of the monomer used to form polymer A.
MUST HAVE A DOUBLE BOND IN
